CN213982466U - Heat tracing device of steam drain pipe - Google Patents

Abstract

The utility model provides a steam drain pipe's companion heat ware, includes the companion heat ware inner tube, companion heat ware inner tube outside is provided with the companion heat ware outer tube, forms the cavity between companion heat ware inner tube and the companion heat ware outer tube, the lower part of companion heat ware outer tube and companion heat ware inner tube lower part welded connection, the outer tube end cover is connected on the upper portion of companion heat ware outer tube, and outer tube end cover is located the companion heat ware inner tube outside, outer tube end cover first is cavity annular cavity, and a steam inlet hole is seted up at the cavity edge, and a plurality of water conservancy diversion holes of hoop evenly distributed are followed to the cavity bottom, and the water conservancy diversion hole communicates with each other with the cavity, lies in companion heat ware outer tube downside and opens and have the steam outlet hole, and the steam outlet hole communicates with each other with the cavity. The utility model discloses under the prerequisite of not obviously developing the whole efficiency of quick-witted group and exerting oneself, avoid the fatigue failure that the hydrophobic pipeline welding seam produced because of the temperature reversal to solve the thermal fatigue problem of steam hydrophobic pipeline.

Description

Heat tracing device of steam drain pipe

Technical Field

The utility model relates to a nuclear power and thermal power plant fortune dimension technical field, in particular to steam trap's companion heat ware.

Background

The steam turbine of the pressurized water reactor nuclear power plant is a saturated steam turbine, the steam extraction humidity of the steam turbine is high, and in the running process of a unit, more hydrophobic water exists in main steam and steam extraction pipelines of the steam turbine. In order to ensure the safety of steam pipelines and equipment and improve the efficiency of a steam system, hydrophobic water in the steam system must be discharged in time, so that a large number of steam traps and steam traps with the functions of hydrophobic water trap and steam stop are used in a nuclear power plant, and a certain amount of steam traps are also arranged in the steam system of the thermal power plant. The temperature and the pressure of the main steam and a steam extraction pipeline of the steam turbine are higher, and the pressure and the temperature in the steam trap and a pipeline in front of the steam trap are higher; the drain is discharged to the condenser through the steam trap, and the temperature and the pressure of the condenser are lower. The intermittent opening of the steam trap and the steam trap can cause the cold and hot alternation of the pipeline to generate thermal stress, so that the weak link is cracked and leaked, and the thermal fatigue failure accidents of the steam trap of the nuclear power plant and the nuclear power plant occur.

The alternating thermal stress of the steam trap and the pipeline behind the steam trap is controlled under the allowable fatigue stress, which is an effective method for solving the thermal fatigue failure. The main methods for reducing the thermal fatigue risk of the drain pipe at present comprise:

(1) the structure of the steam trap is optimized, and the smoothness of drainage, the stability of a flow field and the uniformity of temperature distribution are improved;

(2) the pipeline structure is optimized, the support and hanger arrangement, the tee joint and elbow structures, the pipeline diameter, the wall thickness and the like of the drainage pipeline are improved, and the pipeline thermal stress level is reduced from the aspects of structural form, spatial arrangement and the like;

(3) the material of the pipeline is optimized, different materials have different thermal expansion coefficients, elastic moduli and fatigue strengths in a high-temperature environment, and screening more suitable hydrophobic pipeline material is also an important means for reducing the risk of thermal fatigue;

(4) the optimization of the thermodynamic system reduces the hydrophobic amount, hydrophobic frequency or hydrophobic fluency through the optimization of the thermodynamic system, and is also a means for reducing the risk of thermal fatigue of the pipeline.

The method (1), (2) and (4) mainly have the function of relieving the thermal stress of the pipeline to a certain extent, and complex thermodynamic and structural mechanics simulation analysis needs to be carried out in advance due to large modification workload so as to verify the effectiveness of the implementation scheme and ensure that unacceptable influence on the functions of the original system cannot be generated. The method (3) mainly reduces the risk of fatigue failure by improving the fatigue resistance level of the material, and has relatively limited effect.

Disclosure of Invention

In order to overcome the technical problem, the utility model aims to provide a steam drain pipe's companion heat ware is not obviously developing under the prerequisite of making an uproar unit overall efficiency and exerting oneself, avoids the fatigue failure that the drain pipe welding seam produced because of the temperature reversal to solve steam drain pipe thermal fatigue problem.

In order to realize the purpose, the utility model discloses a technical scheme is:

the utility model provides a steam trap's companion's heat ware, includes companion's heat ware inner tube 1, companion's heat ware inner tube 1 outside is provided with companion's heat ware outer tube 2, forms the cavity between companion's heat ware inner tube 1 and the companion's heat ware outer tube 2, and the lower part of companion's heat ware outer tube 2 and the welded connection in companion's heat ware inner tube 1 lower part, the outer tube end cover 3 is connected on companion's heat ware outer tube 2's upper portion, and outer tube end cover 3 is located companion's heat ware inner tube 1 outside, the first half of outer tube end cover 3 is cavity annular cavity, and a steam inlet is seted up at the cavity edge, and a plurality of water conservancy diversion holes of hoop evenly distributed are followed to the cavity bottom, and the water conservancy diversion hole communicates with each other with the cavity, lies in companion's heat ware outer tube 2 downside and opens there is the steam outlet, and steam outlet communicates with each other with the cavity.

The outer pipe 2 of the heat tracing device is in threaded connection with an outer pipe end cover 3.

The chambers of the inner pipe 1 and the outer pipe 2 of the heat tracing device are fixed relatively through a support 8, and the support 8 is distributed in the pipes at equal intervals.

And a pressing cover 4 is arranged on the outer tube end cover 3, and a double-wedge-shaped sealing ring 5 is arranged between the outer tube end cover 3, the pressing cover 4 and the heat tracing device inner tube 1.

The wedge-shaped surface at one end of the sealing ring 5 is fastened by the upper part of the outer tube end cover 3, and the other end of the sealing ring is fastened by the pressing cover 4; the outer tube end cover 3 and the pressing cover 4 are connected in a positioning mode through a pressing bolt 6 and a pressing nut 7.

The pressing cover 4 is connected with the end cover 3 of the outer pipe of the heat tracing device in a positioning way by a pressing bolt and a pressing nut.

The heat tracing device comprises a heat tracing device inner pipe 1, a heat tracing device outer pipe 2 and an outer pipe end cover 3, wherein the heat tracing device inner pipe 1, the heat tracing device outer pipe 2 and the outer pipe end cover 3 are of separable structures, the heat tracing device outer pipe 2 is welded with a steam trap downstream pipeline during installation, and the outer pipe end cover 3 is mechanically fastened and connected with a steam trap upstream pipeline.

The utility model has the advantages that:

(1) the utility model discloses the heat source of heat tracing comes from the superheated steam of the high parameter steam system of power plant, and the cooling back row provides power to the low parameter steam-water system of power plant through the pressure differential between the different systems, need not install active equipment such as pump, fan, boiler, and steam after the cooling returns power plant thermodynamic cycle system once more, the energy saving, safe and reliable.

(2) Compared with an electric heating heat tracing pipe, the electric heating heat tracing pipe does not relate to electric equipment, steam of an original system of an electric power plant is used for carrying out heat tracing of the drain pipe, and the operation and maintenance cost is greatly reduced.

(3) The medium temperature of the high-parameter steam system of the nuclear power plant has small difference with the temperature of the hydrophobic medium in the hydrophobic pipe sensitive to thermal fatigue, the hydrophobic pipeline is heated by extracting steam through the high-parameter steam system, the problem of temperature alternation of a welding seam behind the steam trap caused by intermittent drainage can be effectively avoided, thermal fatigue stress is fundamentally reduced, and the pipeline and the welding seam are protected to the maximum extent.

(4) The utility model adopts the pipe-in-pipe form, which can fully protect the heat tracing pipeline. Before installation, the outer pipe, the inner pipe and the end cover of the outer pipe of the heat tracing device are of independent structures, are separately installed during installation, are convenient, simple and detachable, and can be periodically checked and maintained.

Drawings

FIG. 1 is a schematic diagram of a heat trace system;

FIG. 2 is a schematic structural view of a heat tracing device;

FIG. 3 is a schematic sectional view of the structure of the heat tracing device;

FIG. 4 is a sectional view taken along line A-A;

FIG. 5 is a sectional view taken along line B-B.

1-an inner pipe (a drain pipe to be heat-traced), 2-an outer pipe of the heat tracing device, 3-an end cover of the outer pipe of the heat tracing device, 4-a pressing cover, 5-a double-wedge-shaped sealing ring, 6-a pressing bolt, 7-a pressing nut and 8-a supporting piece.

Detailed Description

The present invention will be described in further detail with reference to examples.

As shown in fig. 1, the utility model discloses a heat tracing device installs on the steam drain pipe section that probably takes place fatigue, introduce superheated steam through the steam system (such as nuclear power plant catch water reheater export, main steam pipe way of thermal power plant etc.) from power plant superheat degree and pressure are higher, then enter heat tracing device heating drain pipe, the superheated steam who cools discharges into low parameter steam-water system (such as nuclear power plant No. 3 low steam extraction pipeline, thermal power plant cold reheat pipe way etc.), high parameter system and low parameter system automatically generate steam flow because of the pressure differential, the superheated steam who cools discharges into low parameter system and carries out waste heat utilization.

Referring to fig. 1 to 5, a heat tracing device for a steam drain pipe introduces superheated steam from a steam system with higher superheat degree and pressure in a power plant, then the superheated steam enters a heat tracing device to heat the drain pipe, the cooled superheated steam is automatically discharged into a low-parameter steam-water system under the action of system pressure difference to utilize waste heat, and the structure of the heat tracing device comprises a heat tracing device inner pipe 1, a heat tracing device outer pipe 2, a heat tracing device outer pipe end cover 3, a pressing cover 4, a double-wedge-shaped sealing ring 5, a pressing bolt 6, a pressing nut 7 and a supporting piece 8. There is a support 8 between the inner tube 1 and the outer tube 2 of the heat tracing.

The lower part of the heat tracing device outer pipe 2 is welded with the heat tracing device inner pipe 1 (heated drain pipe), the inlet end of the heat tracing device is mechanically fastened and connected with the heated drain pipe, and the fastening end is sealed by a double-wedge-shaped sealing ring. The outer pipe 2 of the heat tracing device is connected with the outer pipe end cover 3 through threads; double wedge-shaped sealing rings 5 are arranged between the heat tracing outer tube end cover 3 and the pipeline and between the pressing cover 4 and the pipeline; the compression cover 4 is connected with the outer pipe end cover 3 of the heat tracing device in a positioning way by a compression bolt 6 and a compression nut 7.

The inner pipe 1, the outer pipe 2 and the outer pipe end cover 3 of the heat tracing device are separable structures. The inner pipe 1 and the outer pipe 2 of the heat tracing device are relatively fixed through the supporting pieces 8, and the supporting pieces 8 are distributed in the pipe at equal intervals, so that the inner pipe and the outer pipe are basically coaxial, and the vibration amplitude of the inner pipe under the action of airflow is limited.

During installation, the supporting piece 8 is directly welded on the inner pipe 1 of the heat tracing device, then the outer pipe 2 of the heat tracing device is sleeved on the drain pipe behind the steam trap, and the outer pipe 2 of the heat tracing device is welded with the inner pipe 1 of the heat tracing device.

The number of supports 8 is distributed in the pipe in equally spaced numbers, as the case may be, depending on the length of the steam trap.

During installation, the outer pipe end cover 3, the double-wedge-shaped sealing ring 5 and the pressing cover 4 are sleeved on a drainage pipeline in front of the steam trap, and the outer pipe end cover 3 is installed on the outer pipe 2 of the heat tracing device through threaded connection, so that a welding seam is positioned inside the heat tracing device.

And finally, the end cover 3 of the outer pipe of the heat tracing device and the external pipeline are sealed by a double-wedge-shaped sealing ring 5, and are positioned and connected by a compression bolt 6 and a compression nut 7 to apply pretightening force, so that the double-wedge-shaped sealing ring 5 is stressed in the radial direction and the axial direction simultaneously to prevent steam leakage.

The upper half part of the outer tube end cover 3 of the heat tracing device is a hollow cavity, the edge of the hollow cavity is provided with a steam inlet hole for introducing superheated steam, the bottom surface of the hollow cavity is symmetrically distributed with a plurality of flow guide holes along the axial direction, and the number of the flow guide holes is 8 in the figure. The steam inlet pipe is used for ensuring that steam uniformly enters the heat exchanger, and the flowing stability and the heat exchange uniformity are improved. The lower half part of the outer pipe end cover 3 of the heat tracing device is provided with internal threads which are connected and sealed with the outer pipe through threads.

During operation, high-temperature steam enters the end cover cavity through the steam inlet hole, then uniformly enters the heat tracing device through the flow guide hole to heat the pipeline, and then exits from the steam outlet hole, so that the heat tracing device is always in a heating state.

Claims (6)

1. The utility model provides a steam trap's companion heat ware, its characterized in that, includes companion heat ware inner tube (1), companion heat ware inner tube (1) outside is provided with companion heat ware outer tube (2), forms the cavity between companion heat ware inner tube (1) and companion heat ware outer tube (2), and the lower part and companion heat ware inner tube (1) lower part welded connection of companion heat ware outer tube (2), outer tube end cover (3) are connected on the upper portion of companion heat ware outer tube (2), and outer tube end cover (3) are located companion heat ware inner tube (1) outside, the first half of outer tube end cover (3) is cavity annular cavity, and a steam inlet is seted up at the cavity edge, and a plurality of water conservancy diversion holes of hoop evenly distributed are followed to the cavity bottom, and water conservancy diversion hole and cavity communicate with each other, are located companion heat ware outer tube (2) downside and have the steam outlet, and steam outlet communicates with each other with the cavity.

2. The heat tracing of a steam trap according to claim 1, wherein the outer pipe (2) of the heat tracing is screwed with the outer pipe end cap (3).

3. The heat tracing of a steam trap according to claim 1, wherein the chambers of the inner pipe (1) and the outer pipe (2) are fixed relatively by means of supports (8), and the supports (8) are distributed in plurality at equal intervals in the pipes.

4. The heat tracing device of the steam hydrophobic pipeline according to claim 1, characterized in that the outer pipe end cap (3) is provided with a pressing cap (4), and a double wedge-shaped sealing ring (5) is arranged between the outer pipe end cap (3), the pressing cap (4) and the inner pipe (1) of the heat tracing device.

5. The heat tracing device of a steam trap pipe according to claim 4, wherein the wedge-shaped surface of one end of the sealing ring (5) is fastened by the upper part of the outer pipe end cover (3), and the other end is fastened by the pressing cover (4); the outer tube end cover (3) is connected with the compression cover (4) in a positioning way through a compression bolt (6) and a compression nut (7).

6. The heat tracing device of the steam trap pipe according to claim 1, wherein the inner pipe (1), the outer pipe (2) and the outer pipe end cap (3) are separable structures, the outer pipe (2) is welded with the downstream pipe of the trap during installation, and the outer pipe end cap (3) is mechanically fastened with the upstream pipe of the trap.

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